DbContext's DbSet member throws InvalidCastException upon DbSet.ToArray(), trying to cast to another declared entity type

Question

I'm using EntityFrameworkCore 7.0 in conjunction with Pomelo.EntityFrameworkCore.MySql to build a Code-First app relying on MySQL.

I'm using the Fluent Api and IEntityTypeConfiguration<> implementations for each and every entity class there is in my model assembly.

At one point, my DbContext declares this property:

public class SassyDbContext : DbContext
{
   private DbSet SassyUsers { get; set; }
}

It's supposed to expose objects of type SassyUser, defined as such :

public class SassyUser : IdentifiedObjectBase // abstract implementation of the Id PK.
    {
        private DateTime? _creationDate = null;
        private static readonly byte[] __ = new byte[] { 0xd2, 0xc2, 0xd6, 0xcd, 0xb0, 0x1d, 0x4b, 0x80, 0xbe, 0x60, 0x54, 0x82, 0xb1, 0xfa, 0x9a, 0xc3 };


        public SassyUser() { }


        public string FirstName { get; set; } = string.Empty;
        public string LastName { get; set; } = string.Empty;

        public string Pseudonym {
            get => ModelUtils.DeScrambleString(__, PseudonymEnc);
            set => PseudonymEnc = ModelUtils.ScrambleString(__, value);
        }

        private ICollection AuthoredAssets { get; set; } = new HashSet();
        private ICollection RevisedAssets { get; set; } = new HashSet();

        private ICollection AuthoredTraits { get; set; } = new HashSet();
        private ICollection RevisedTraits { get; set; } = new HashSet();


        private ICollection ImportSessions { get; set; } = new HashSet();

        public string PseudonymEnc { get; set; } = string.Empty;



        public string Password {
            get => ModelUtils.DeScrambleString(__, PasswordEnc);
            set => PasswordEnc = ModelUtils.ScrambleString(__, value);
        }

        public string PasswordEnc { get; set; } = string.Empty;


        public string? Email {
            get => ModelUtils.DeScrambleString(__, EmailEnc!);
            set => EmailEnc = ModelUtils.ScrambleString(__, value!);
        }
        public string? EmailEnc { get; set; } = null;


        public DateTime? CreationDate {
            get {
                if (_creationDate is null)
                    _creationDate = DateTime.Now.ToUniversalTime();
                return _creationDate;
            }
            set {
                if (value is not null)
                    _creationDate = value.Value.ToUniversalTime();
            }
        }


        public Privileges GlobalPrivileges { get; set; } = Privileges.None;


        public bool CanAddAssets(SassyDataset? dataset)
        {
            throw new NotImplementedException();
        }

        public bool CanEdit(AnnotatedAsset asset)
            => CanEdit(asset?.Id ?? null);

        public bool CanEdit(long? assetId)
        {
            throw new NotImplementedException();
        }


    }

And here is its configurator implementation :

 internal class SassyUserConfig : IEntityTypeConfiguration
    {
        public SassyUserConfig() { }

        public void Configure(EntityTypeBuilder builder)
        {

            builder.Ignore(e => e.Pseudonym);
            builder.Ignore(e => e.Password);
            builder.Ignore(e => e.Email);
            builder.Ignore("_creationDate");


            builder
                .Property(e => e.CreationDate)
                .HasField("_creationDate")
                .UsePropertyAccessMode(PropertyAccessMode.Property)
                .IsRequired(true);


            builder
                .Property(e => e.EmailEnc)
                .IsUnicode(false)
                .HasColumnName("email")
                .HasCharSet("ASCII")
                .UseCollation("ascii_general_ci")
                .IsRequired(false);

            builder
                .Property(e => e.FirstName)
                .IsUnicode()
                .IsRequired(false);

            builder
                .Property(e => e.LastName)
                .IsUnicode()
                .IsRequired(false);

            builder
                .Property(e => e.GlobalPrivileges)
                .HasConversion()
                .HasDefaultValue(Privileges.None)
                .IsRequired(true);

            builder
                .Property(e => e.PseudonymEnc)
                .IsUnicode(false)
                .HasColumnName("jlgkj")
                .HasCharSet("ASCII")
                .UseCollation("ascii_general_ci")
                .IsRequired();

            builder
              .Property(e => e.PasswordEnc)
              .HasColumnName("fdsqqf")
              .IsUnicode(false)
              .HasCharSet("ASCII")
              .UseCollation("ascii_general_ci")
              .IsRequired();

            builder
                .UseTpcMappingStrategy()
                .ToTable("SassyUsers");

        }
    }

But here's the problem... This DbContext method:

    public SassyUser GetUser(string uide, string pwde)
            => (from usr in SassyUsers 
                where usr.PseudonymEnc == uide && usr.PasswordEnc == pwde 
                select usr).FirstOrDefault()!;

Throws an InvalidCastException upon return of the query, stating:

System.InvalidCastException
  HResult=0x80004002
  Message=Unable to cast object of type 'Sassy.Model.SassyDataset' to type 'Sassy.Model.SassyUser'.
  Source=Microsoft.EntityFrameworkCore.Relational
  StackTrace:
   at Microsoft.EntityFrameworkCore.Query.Internal.SingleQueryingEnumerable`1.Enumerator.MoveNext() in /_/src/EFCore.Relational/Query/Internal/SingleQueryingEnumerable.cs:line 179
   at System.Linq.Enumerable.TryGetSingle[TSource](IEnumerable`1 source, Boolean& found) in /_/src/libraries/System.Linq/src/System/Linq/Single.cs:line 88
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryCompiler.Execute[TResult](Expression query) in /_/src/EFCore/Query/Internal/QueryCompiler.cs:line 68
   at Microsoft.EntityFrameworkCore.Query.Internal.EntityQueryProvider.Execute[TResult](Expression expression) in /_/src/EFCore/Query/Internal/EntityQueryProvider.cs:line 63
   at Sassy.Model.SassyDbContext.GetUser(String uide, String pwde) in S:\sources\C#\Sassy_WPF\SassyDataModel\SassyDbContext.cs:line 262
   at Sassy.AssetsExporter.ExportWorkhorse._worker_DoWork(Object sender, DoWorkEventArgs e) in S:\sources\C#\Sassy_WPF\SassyAssetExporter\ExportWorkhorse.cs:line 169

  This exception was originally thrown at this call stack:
    Microsoft.EntityFrameworkCore.Query.Internal.SingleQueryingEnumerable.Enumerator.MoveNext() in SingleQueryingEnumerable.cs
    System.Linq.Enumerable.TryGetSingle(System.Collections.Generic.IEnumerable, out bool) in Single.cs
    Microsoft.EntityFrameworkCore.Query.Internal.QueryCompiler.Execute(System.Linq.Expressions.Expression) in QueryCompiler.cs
    Microsoft.EntityFrameworkCore.Query.Internal.EntityQueryProvider.Execute(System.Linq.Expressions.Expression) in EntityQueryProvider.cs
    Sassy.Model.SassyDbContext.GetUser(string, string) in SassyDbContext.cs
    Sassy.AssetsExporter.ExportWorkhorse._worker_DoWork(object, System.ComponentModel.DoWorkEventArgs) in ExportWorkhorse.cs

How by the devil should a DbSet try to cast its queries results to SassyDataset when the query result is explicitely typed to SassyUser ? None of those classes inherit each other. They both inherit IdentifiedObjectBase, which is an abstract class that declares and exposes one member, namely:

long? IdentifiedObjectBase.Id {get; set;}

I'm stumped ! Please help !

I fist thought I had mislabeled my tables... But nope... As you can see in the SassyUserConfig class, the table is explicitely named after the entity class 'SassyUser' -> 'SassyUsers' .

Upon successful creation of the schema after a quick SassyDbContext.Database.EnsureCreated(), I add a single SassyUser entity to the database. No the Db report a new row in the SassyUsers table. Nice.

But the DbSet SassydbContext.SassyUsers property keeps spouting InvalidCastExceptions upon query returns.

I also tried to call the SassydbContext.SassyUsers.ToArray() extension method on the incriminated DbSet : same effect. The problem lies withing a misnaming inside the model itself.

Here's a debug trace of EF on this :

dbug: 26/06/2023 21:45:07.048 CoreEventId.QueryCompilationStarting[10111] (Microsoft.EntityFrameworkCore.Query) 
      Compiling query expression: 
      'DbSet()'
dbug: 26/06/2023 21:45:07.058 CoreEventId.QueryExecutionPlanned[10107] (Microsoft.EntityFrameworkCore.Query) 
      Generated query execution expression: 
      'queryContext => new SingleQueryingEnumerable(
          (RelationalQueryContext)queryContext, 
          RelationalCommandCache.QueryExpression(
              Projection Mapping:
                  EmptyProjectionMember -> Dictionary { [Property: IdentifiedObjectBase.Id (long?) Required PK AfterSave:Throw ValueGenerated.OnAdd, 0], [Property: SassyUser.CreationDate (_creationDate, DateTime?) Required PropertyAccessMode.Property, 1], [Property: SassyUser.EmailEnc (string) Ansi, 2], [Property: SassyUser.FirstName (string), 3], [Property: SassyUser.GlobalPrivileges (Privileges) Required ValueGenerated.OnAdd, 4], [Property: SassyUser.LastName (string), 5], [Property: SassyUser.PasswordEnc (string) Required Ansi, 6], [Property: SassyUser.PseudonymEnc (string) Required Ansi, 7] }
              SELECT s.Id, s.CreationDate, s.email, s.FirstName, s.GlobalPrivileges, s.LastName, s.fdsqqf, s.jlgkj
              FROM SassyUsers AS s), 
          ReaderColumn[] { ReaderColumn, ReaderColumn, ReaderColumn

DbContext's DbSet<> member throws InvalidCastException upon DbSet.ToArray(), trying to cast to another declared entity type

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